{"id":51618,"date":"2023-04-11T05:23:00","date_gmt":"2023-04-11T05:23:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=51618"},"modified":"2023-04-12T20:47:59","modified_gmt":"2023-04-12T20:47:59","slug":"sentinel-1a-sar-observations-over-hawaii-late-on-10-april","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/51618","title":{"rendered":"Sentinel-1A SAR Observations over Hawai&#8217;i late on 10 April"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1ASAR_0to35_G18Band02_0to20-20230411_04z.gif\"><img loading=\"lazy\" decoding=\"async\" width=\"1385\" height=\"751\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1ASAR_0to35_G18Band02_0to20-20230411_04z.gif\" alt=\"\" class=\"wp-image-51619\"\/><\/a><figcaption class=\"wp-element-caption\">Sentinel-1A SAR Winds (from 0-35 knots) overlain on top of a brightened GOES-18 Visible image (Reflectances are from 0-20%), 0440 UTC on 11 April 2023 (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n<p>Sentinel-1A overflew the central Hawai&#8217;ian islands near sunset on 10 April 2023, and the SAR data collected are shown above.  Data are also available online at <a href=\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/sarwinds_daily_rcs.html?date=20230411\">this website<\/a>.  The toggles below compare wind speed from that website (<a href=\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-04\/S1A_ESA_2023_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C5_GFS025CDF_wind.png\">04:39:48<\/a> and <a href=\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-04\/S1A_ESA_2023_04_11_04_40_19_0734503219_158.29W_22.52N_VV_C5_GFS025CDF_wind.png\">04:40:19<\/a> from south to north) with Normalized Radar Cross Section fields (<a href=\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-04\/S1A_ESA_2023_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C_nrcs.png\">04:39:48<\/a> and <a href=\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-04\/S1A_ESA_2023_04_11_04_40_19_0734503219_158.29W_22.52N_VV_C_nrcs.png\">04:40:19<\/a>).  The character of the wind fields are much different north and south of the Hawai&#8217;ian Island chain, with the southern winds showing marked funneling between islands, and smaller regions of lighter winds in the lee of the islands.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C_wind_nrcs.toggle.gif\"><img decoding=\"async\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C_wind_nrcs.toggle.gif\" alt=\"\" class=\"wp-image-51621\"\/><\/a><figcaption class=\"wp-element-caption\">Sentinel-1A Derived Winds and Normalized Radar Cross Section (NRCS) field, 04:39:48 UTC on 11 April 2023 (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_04_11_04_40_19_0734503219_158.29W_22.52N_VV_C_wind_nrcs.toggle.gif\"><img decoding=\"async\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_04_11_04_40_19_0734503219_158.29W_22.52N_VV_C_wind_nrcs.toggle.gif\" alt=\"\" class=\"wp-image-51622\"\/><\/a><figcaption class=\"wp-element-caption\">Sentinel-1A Derived Winds and Normalized Radar Cross Section (NRCS) field, 04:40:19 UTC on 11 April 2023 (Click to enlarge)<\/figcaption><\/figure>\n\n\n\n<p>The Slider below shows the SAR wind field north of Hawai&#8217;i with the brightened GOES-18 Visible imagery. There is excellent correspondence between local wind maxima and cloud features (presumably showers).  Sometimes, the strongest SAR winds are associated with misinterpretation of strong reflection from cloud ice by the SAR Wind algorithm;  when that happens, &#8216;feathery&#8217; structures are usually apparent in the NRCS field.  There is little evidence of that happening in the SAR winds above.<\/p>\n\n\n<div\n\t\tclass=\"ssec_slider_juxtapose\"\n\t\tid=\"ssec_slider_juxtapose_881371033\"\n\t\tdata-left-src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/G18Band02_0to20_ZoomN-20230411_044019-1024x555.png\"\n\t\tdata-left-label=\"GOES-18 Brightened Band 2 (0-20%)\"\n\t\tdata-right-src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1ASAR_0to35_G18Band02_0to20_ZoomN-20230411_044019-1024x555.png\"\n\t\tdata-right-label=\"Sentinel-1A SAR Winds (0-35 knots)\"\n\t\tdata-width=\"1385\"\n\t\tdata-height=\"751\"\n\t\tdata-left-orig-src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/G18Band02_0to20_ZoomN-20230411_044019.png\"\n\t\tdata-right-orig-src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1ASAR_0to35_G18Band02_0to20_ZoomN-20230411_044019.png\">\n\t<span class=\"ssec_slider_juxtapose_fullscreen_button\">\n\t\t<span class=\"fullscreen-icon\"><svg viewBox=\"0 0 12 12\" preserveAspectRatio=\"xMidYMid\" tabindex=\"-1\">\n\t\t\t<polyline class=\"fill\" points=\"6,6 5.9,2 4.9,3 2.9,1 1,2.9 3,4.9 2,5.9\"\n\t\t\t\t\t  transform=\"translate(6,6)\"><\/polyline>\n\t\t\t<polyline class=\"fill\" points=\"6,6 5.9,2 4.9,3 2.9,1 1,2.9 3,4.9 2,5.9\"\n\t\t\t\t\t  transform=\"translate(6,6) rotate(90)\"><\/polyline>\n\t\t\t<polyline class=\"fill\" points=\"6,6 5.9,2 4.9,3 2.9,1 1,2.9 3,4.9 2,5.9\"\n\t\t\t\t\t  transform=\"translate(6,6) rotate(180)\"><\/polyline>\n\t\t\t<polyline class=\"fill\" points=\"6,6 5.9,2 4.9,3 2.9,1 1,2.9 3,4.9 2,5.9\"\n\t\t\t\t\t  transform=\"translate(6,6) rotate(270)\"><\/polyline>\n\t\t\t<\/svg>\n\t\t<\/span>\n\t<\/span>\n<\/div>\n\n\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>Sentinel-1A has a 12-day repeat cycle, so the same domain as above should have been duplicated 12 days earlier, late in the day on 29 March (or around 0400 UTC on 30 March).  The toggle below compares the data at 04:39:37 on 30 March and 04:39:38 on 11 April.  This scene should be repeated on 23 April this month.  <a href=\"https:\/\/www.esa.int\/\">ESA<\/a> does provide kml files that show when the next collections will happen (<a href=\"https:\/\/sentinel.esa.int\/web\/sentinel\/missions\/sentinel-1\/observation-scenario\/acquisition-segments\">link<\/a>).<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_03_30_04_39_47_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C5_GFS025CDF_wind_toggle.gif\"><img loading=\"lazy\" decoding=\"async\" width=\"2114\" height=\"1955\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2023\/04\/S1A_ESA_2023_03_30_04_39_47_04_11_04_39_48_0734503188_157.90W_20.62N_VV_C5_GFS025CDF_wind_toggle.gif\" alt=\"\" class=\"wp-image-51631\"\/><\/a><figcaption class=\"wp-element-caption\">Sentinel-1A Derived SAR Winds, 04:39:47 UTC on 30 March and 04:38:48 UTC On 11 April 2023 (Click to enlarge)<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Sentinel-1A overflew the central Hawai&#8217;ian islands near sunset on 10 April 2023, and the SAR data collected are shown above. Data are also available online at this website. The toggles below compare wind speed from that website (04:39:48 and 04:40:19 from south to north) with Normalized Radar Cross Section fields (04:39:48 and 04:40:19). The character [&hellip;]<\/p>\n","protected":false},"author":19,"featured_media":51634,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[114,104,25],"tags":[],"class_list":["post-51618","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-18","category-sar","category-satellite-winds"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51618","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=51618"}],"version-history":[{"count":11,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51618\/revisions"}],"predecessor-version":[{"id":51640,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/51618\/revisions\/51640"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/51634"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=51618"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=51618"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=51618"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}